One of the best tips I ever found was something someone used for marking tomato plants, but it works for just about anything in the garden. Colored flagging tape (any hardware store) and a black sharpie marker for the name of my vegetables. I tie it onto cages, stakes, and trellises. For marking row vegetables I tie the flags onto small sticks that I either pick up from the yard or cut from brush. This also helps identify the location of small plants surrounded by heavy mulch early in the season. I have tied them onto the plants themselves but the flags tend to get covered up by leaves quickly.
Although I have never had really bad fading of the marker I put the name on both sides of the tape just in case. I like the pink tape. It is a bit more cheerful than "warning orange". I suppose if you could score some "police line" or Biohazard tape it might keep the neighbors from raiding your garden... Won't work for illiterate deer though.